The dye thermal transfer printing method is capable of providing an image of high quality equal to that of color photography, and an apparatus employed in the method is compact, is easily maintained and can operate instantaneously. In the dye thermal transfer printing method, a transfer member having a coloring material layer, which contains sublimining dye, on a thin film base, and an image-receptor having a dyeing layer on a thick film such as a synthetic paper or the like, are overlapped on each other, and the subliming dye is transferred into the dyeing layer by a thermal recording head, thus recording a mixed color image of dye molecules.
On the other hand, in order to affix the printed image onto various materials, the method of employing tack sheets has been proposed. In this method, the image-receptor has a double-layer structure, and an adhesive material is applied onto a reverse surface of a base material formed with an upper dyeing layer so that the base material is fixed on a support member formed with a lower parting layer. After printing, the upper layer is separated or peeled off and then is fixed on a post-card, etc.
Printed images made by the dye thermal transfer printing method are formed on specially prepared paper sheets, so that the running cost is high, preventing the printing technique from spreading widely to general applications.
Moreover, in this multi-media age, information includes images mixed with characters. Even though there is a strong demand for printing such information on plain paper in a similar manner as in a copying apparatus, it has been impossible to obtain an image of high quality on a plain paper sheet by the conventional dye thermal transfer printing method.
Thus, U.S. Pat. No. 5,284,814 discloses a dye thermal transfer printing method for forming full-color picture images of high quality on any image-receptor. In the method, a dyeing layer transfer member having a lubricating heat-resistant layer on the reverse surface of a first base material and a dyeing layer on the other surface, an ink transfer member having a lubricating heat-resistant layer on the reverse surface of a second base material and an ink layer on the other surface, an intermediate member having a functional layer on a third base material, and an image-receptor are all used. The dyeing layer is thermally transferred onto the functional layer of the intermediate member; dye in the ink layer is thermally transferred and recorded in response to image signals onto the dyeing layer--which was transferred on the functional layer--by setting a thermal head in contact with the lubticating heat-resistant layer; the dyeing layer recorded with the dye is then thermally transferred onto the main surface of the image-receptor.
However, it is difficult to repeatedly form full-color picture images of high quality with stability by the conventional dyeing layer transfer member and ink transfer member, especially without influence by the surrounding environment.
Moreover, in the above-mentioned conventional dye thermal transfer printing method, unrecorded spaces are formed around the peripheral section of an image-receptor, and it is impossible to form picture images on the entire surface of an image-receptor.